OSPF - route filtering

OSPF - route summarization

OSPF


In an [OSPF](/ospf) topology, there can be many [areas](/ospf-backbone-area-0) defined.  Counterintuitively, OSPF routers do not belong to OSPF areas, but it is **individual interfaces of OSPF routers that are assigned to areas**.

Thus, it is inaccurate to state that particular routers belong to specific areas, unless all of their interfaces are within the area in question.

Routers with interfaces assigned to more than one area are considered Area Border Routers [area border routers](/ospf-abr-and-loop-prevention) or ABRs.  As is evident, it is not possible to state that an ABR belongs to any particular area, since it, by definition "belongs" to more than one.

Links:

https://networklessons.com/ospf/introduction-to-ospf

https://networklessons.com/ospf/ospf-multi-area-configuration

OSPF within what area is an OSPF router considered to be

OSPF Hello packets unicast and multicast

OSPF IP Unnumbered

OSPF IS-IS comparison

OSPF Incremental SPF and receipt of LSAs

OSPF LSA Recursion

OSPF LSA Sequence Numbers

OSPF LSA Types

OSPF NSSA ABR advertises default route

OSPF Not So Stubby Area NSSA

OSPF Path selection

OSPF Routing Bit

OSPF SPF Scheduling and throttling timers

OSPF TTL Security Check

OSPF Troubleshooting

OSPF Type 4 LSA

OSPF Type 5 LSA

OSPF Type 7 LSA

OSPF Why it is not suitable for use on the Internet

OSPF advertising loopback network

OSPF area inactive

OSPF area notation

OSPF area type mismatch

OSPF backbone area 0

OSPF default metric values

OSPF design - when to create a new area

OSPF does not redistribute default route

OSPF downheap LSA

OSPF duplicate router IDs

OSPF extent of reconvergence process

OSPF immediate hello packet

OSPF in a GRE multipoint environment

OSPF loop prevention

OSPF master slave election

OSPF message options field

OSPF metric sum of outgoing interface costs

OSPF modifying the router ID

OSPF network command

OSPF network types

OSPF non directly connected neighbor adjacencies

OSPF packet types

OSPF point to point network type for Ethernet

OSPF requirements for forming adjacency

OSPF router ID in an IPv6 environment

OSPF router ID

OSPF sham-link cost

OSPF sham-link

OSPF virtual link and ABRs

OSPF where do you configure a virtual link

OSPF why is a backbone area 0 necessary

OSPFv2 and OSPFv3 comparison

OSPFv3 - router ospfv3 command

OSPFv3 communication between routers and next hop addresses

OSPFv3 instance ID

Offset-list

PAT (overloading) maximum number of translations per inside global address

PAgP

PBR - Policy Based Routing

PBR - Transport Layer port number

PBR - load balancing

PBR - matching prefix lists

PBR - route-map and ACL deny statements not supported

PBR - set interface command

PBR next hop recursive

PBR next hop verify availability

PBR next-hop and default next-hop

PPPoE

PSTN

PTP - Best Master Clock Algorithm

PTP - Clock Types

PTP - Interface Roles

PTP - Offset and Delay times

PTP - Precision Time Protocol

Passive interface

Physical layer - Copper medium

Physical layer - Optical fiber medium

Physical layer - Wireless medium

Physical layer - carrier wave

Physical layer - encoding

Physical layer - media

Physical layer - modem

Physical layer - modulation

Ping - Specify ToS

Ping - common reasons for failure

Ping - debug commands

Ping - possible ping responses

Ping - sweep range of sizes

Ping - troubleshooting concepts

Ping

PoE - Understanding Maximum Power

PoE Passive

PoE Standards-based

PoE over Gigabit Ethernet

PoE power sourcing equipment (PSE)

PoE powered device (PD)

PoE what is it

Point-to-Point Protocol (PPP)

Policy Based Routing acts on incoming traffic

Prefix Lists - Operators

OSPF within what area is an OSPF router considered to be

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